(a) Technical Field of the Invention
The present invention is related to a light emitting diode (LED) optical energy detection and feedback system, and more particularly, to one that executes throughput detection and feedback when the LED array in a flat fluorescent light (FFL) source is emitting light to make sure the white balance of the LED array light source.
(b) Description of the Prior Art
The FFL source is a very important light source for the LCD. As illustrated in one, an FFL source 1 of the prior art is essentially comprised of a light guide plate 10, multiple light diffusion devices 11 are disposed on the light emitting plane of the light guide plate 10 to serve as the light convergence 12 that converges and guide the correct light emitting direction. Multiple light guide points 103 in extremely great number are provided on a reflection plane 102 of the light guide plate 10, a reflection plate 103 is adhered onto the reflection plane 102. One incidence plane 104 as a minimum is provided in the light guide plate 10 and an LED array 14 of LED (light emitting diode) lamps are disposed external to the light incidence plane 104. The LED array 14 is comprised of a red LED lamp set 141, a green LED lamp set 142, and a blue LED lamp set 143 connected in series.
As illustrated in FIG. 2, all three RGB LED lamp sets 141, 142, 143 of the LED array 14 emit light at the same time to the incidence plane 104 of the light guide plate 10 while mixing the light colors into a final white light source to forthwith transmit into the light guide plate 10, deflected through those multiple light guide points 103 and the reflection plate 102 to the light diffusion device 11 where the light source is softened before being converged by the light convergence device 12 to leave the FFL source 1 for the liquid crystal panel.
Furthermore, before the assembly, it must be tested and confirmed that every LED in each of the red LED set 141, the green LED set 142, and the blue LED set 143 respectively provides the same characteristics in its LED set by conducting each LED an identical amperage of current to screen parameters measured in three close frequencies of light strength, color, and v/f to be further classified (Bin). To meet the preset white light performance after the mix of LED light colors, i.e., the white balance, RGB LED sets are respectively selected depending on the specification requirements of the product and the allowances set forth by respectively LED manufactures of the individual color for final assembly of the LED array 14.
However, after the operation for a certain period of time, some device may become weak and instable. It is usually found that a certain LED lamp set in the LED array 14 is observed with poor performance in optical energy resulting in the failure of the white light mixed by the entire LED array 14 to meet white balance conditions, thus to compromise the subsequent application of the light source. Whereas the failure in meeting white light balance conditions is usually found after the product has been delivered to the end-user, there is no way to determine which set or how many sets of the LED went wrong. The modulus design of the product makes practically impossible to follow up with any betterment or repair. Therefore, how to maintain detect the output of the optical energy from each LED lamp set at any time and from time to time after the LED array 14 is adapted to the FFL 1, followed with the remedies as required depending on the detection results remains the bottleneck pending an urgent breakthrough by the trades concerned.